---
title: "Recessive — AP Bio Definition & Exam Guide"
description: "A recessive allele only shows up in the phenotype when an organism has two copies. Master it for Mendelian genetics, Punnett squares, and pedigree FRQs in Unit 5."
canonical: "https://fiveable.me/ap-bio/key-terms/recessive"
type: "key-term"
subject: "AP Biology"
---

# Recessive — AP Bio Definition & Exam Guide

## Definition

A recessive trait or gene is one that can be carried in a person's genes without appearing in that person. It can only be expressed (appear) when two copies are present (one from each parent).

## Related Study Guides

- [5.3 Mendelian Genetics](/ap-bio/unit-5/mendelian-genetics/study-guide/SdlMbZYAD4sxuXuRygPv)

## Review

### Related Terms

- [Heterozygous](/ap-bio/key-terms/heterozygous): Refers to having inherited different forms of a particular gene from each parent.
- Carrier: An individual who carries and is capable of passing on a genetic mutation associated with disease and may or may not display disease symptoms.
- [Punnett Square](/ap-bio/key-terms/punnett-square): A diagram that is used to predict an outcome of a particular cross or breeding experiment.